1. Field of the Invention
The present invention relates to a temperature control method for a refrigerator, and more particularly to a temperature control method for a refrigerator which can supply cold air to insufficiently cooled regions in a refrigerating compartment of the refrigerator without an additional turning-on of a compressor and circulating fan included in the refrigerator, thereby being capable of minimizing a temperature deviation of the refrigerating compartment while minimizing the power consumption of the refrigerator.
2. Description of the Related Art
Generally, a refrigerator is an apparatus in which freezing and refrigerating compartments are maintained at desired low temperatures by a refrigerant cooling cycle consisting of a compressor, a condenser, a capillary valve, and an evaporator.
FIG. 1 is a perspective view of a conventional refrigerator, illustrating the condition in which freezing and refrigerating compartments are in an opened state.
As shown in FIG. 1, the conventional refrigerator includes a refrigerator body in which a freezing compartment F and a refrigerating compartment R are defined by a barrier 2 at opposite sides of the barrier 2, respectively. A freezing compartment door 4 is hingably mounted to the refrigerator body in front of the freezing compartment F. A refrigerating compartment door 6 is also hingably mounted to the refrigerator body in front of the refrigerating compartment R.
FIG. 2 is a front view showing the inner structure of the conventional refrigerator. FIG. 3 is a side view showing the inner structure of the refrigerating compartment in the conventional refrigerator.
An evaporator 8 is installed in rear of the freezing compartment F. The evaporator 8 absorbs heat from air in the freezing compartment F or refrigerating compartment R through heat exchange between the air and a refrigerant passing through the evaporator 8. In accordance with the heat absorption, the refrigerant evaporates. A circulating fan 10 is also installed in rear of the freezing compartment F in order to forcibly convect the air, cooled in accordance with the heat absorption of the evaporator 8, into the freezing compartment F or refrigerating compartment R.
The freezing compartment F is provided, at the upper portion of a rear wall thereof, with cold air discharge holes 12 adapted to discharge the air cooled by the evaporator 8, that is, cold air, into the freezing compartment F in accordance with the operation of the circulating fan 10. The freezing compartment F is also provided, at the lower portion of the rear wall thereof, with cold air return holes 14 adapted to return the cold air, used to cool the freezing compartment F to a desired freezing temperature, to the evaporator 8.
The freezing compartments F is partitioned into a plurality of freezing chambers F1 to F6. A plurality of shelves 15 to 19 are installed in the freezing chamber F such that they are vertically spaced apart from one another. Food or containers may be laid on the shelves 15 to 19.
The barrier 2 is provided, at its upper portion, with a cold air discharge duct 21 for partially discharging the cold air produced by the evaporator 8 into the refrigerating compartment R in accordance with the operation of the circulating fan 10. The barrier 2 is also provided, at its lower portion, with a cold air return duct 22 for returning the cold air, used to cool the freezing compartment F to a desired freezing temperature, to the evaporator 8.
A damper 24 is installed at one side of the cold air discharge duct 21 or at the upper portion of the refrigerating compartment R. The damper 24 is opened or closed to determine whether nor not the cold air has to be discharged into the refrigerating compartment R.
On the other hand, the refrigerating compartment R is partitioned into a plurality of refrigerating chambers R1 to R6. A plurality of refrigerating compartment shelves 25 to 28 are installed in the refrigerating chamber R such that they are vertically spaced apart from one another. Food or containers may be laid on the refrigerating compartment shelves 25 to 28.
A plurality of baskets 31 to 35 adapted to receive food or containers are mounted to the back surface of the refrigerating compartment door 6 such that they are vertically spaced apart from one another.
The refrigerating compartment shelves 25 to 29 are spaced apart from the baskets 31 to 35 respectively arranged adjacent thereto and from the back surface of the refrigerating compartment door 6, so as to define a cold air passage.
The reference numeral 44 designates a freezing compartment temperature sensor for sensing a temperature at one side of the freezing compartment F, and the reference numeral 45 designates a refrigerating compartment temperature sensor for sensing a temperature at one side of the refrigerating compartment R.
FIG. 4 is a control block diagram of the conventional refrigerator.
As shown in FIG. 3, the conventional refrigerator further includes a compressor 41 for compressing a gaseous refrigerant of low temperature and low pressure emerging from the evaporator 8, thereby producing a gaseous refrigerant of high temperature and high pressure, a condenser for discharging heat from the gaseous refrigerant of high temperature and high pressure into the atmosphere, thereby condensing the gaseous refrigerant to produce a liquid refrigerant of intermediate temperature and high pressure, a capillary valve for reducing the pressure of the high-pressure liquid refrigerant emerging from the condenser, and a compressor cooling fan 42 for cooling the compressor 41 in order to prevent the compressor 41 from over-heating.
The refrigerator also includes a temperature setting unit 43 for setting predetermined maximum and minimum temperatures of the freezing and refrigerating compartments F and R, and a control unit 46 for comparing sensed temperatures of the freezing and refrigerating compartments F and R with the predetermined maximum and minimum temperatures associated therewith, respectively, thereby controlling the opening/closing of the damper 24 and the turning-on/off of the circulating fan 10, compressor 41, and compressor cooling fan 42.
The predetermined maximum and minimum temperatures may be set to correspond to a temperature obtained by adding a predetermined temperature tolerance to a desired temperature set by the user, and a temperature obtained by deducting the predetermined temperature tolerance from the set temperature, respectively. Alternatively, the predetermined maximum and minimum temperatures may be independently set.
Now, a temperature control method for the conventional refrigerator having the above mentioned configuration will be described.
FIG. 5 is a flow chart illustrating the temperature control method for the conventional refrigerator.
First, the control unit 46 compares the temperature Tf of the freezing compartment F sensed by the freezing compartment temperature sensor 44 with the predetermined maximum temperature Tfmax of the freezing compartment F (S1).
The predetermined maximum freezing compartment temperature Tfmax corresponds to a temperature obtained by adding a predetermined temperature tolerance to a desired freezing compartment temperature set by the user.
The control unit 46 turns on the circulating fan 10, compressor 41, and compressor cooling fan 42 when it determines that the temperature Tf of the freezing compartment F is equal to or more than the predetermined maximum temperature Tfmax of the freezing compartment F (S2).
When the circulating fan 10 and compressor 41 are turned on, air present in the freezing compartment F circulates between the evaporator 20 and the freezing compartment F, thereby causing the freezing compartment F to be cooled to a desired freezing temperature.
Thereafter, the control unit 46 compares the temperature Tr of the refrigerating compartment R sensed by the refrigerating compartment temperature sensor 45 with the predetermined maximum temperature Trmax of the refrigerating compartment R (S3).
The predetermined maximum refrigerating compartment temperature Trmax corresponds to a temperature obtained by adding a predetermined temperature tolerance to a desired refrigerating compartment temperature set by the user.
The control unit 46 opens the damper 24 when it determines that the temperature Tr of the refrigerating compartment R is equal to or more than the predetermined maximum temperature Trmax of the refrigerating compartment R (S4).
When the damper 24 is opened, a part of the air cooled by the evaporator 8 is discharged into the refrigerating compartment R via the cold air discharge duct 21. The discharged cold air cools the interior of the refrigerating compartment R to a desired refrigerating temperature while being convected in the interior of the refrigerating compartment R. Subsequently, the cold air flows toward the lower portion of the refrigerating compartment R, and then returns to the evaporator 8 through the cold air return duct 22.
On the other hand, if it is determined at step S3 that the temperature Tr of the refrigerating compartment R is less than the predetermined maximum temperature Trmax of the refrigerating compartment R, the control unit 46 then compares the temperature Tr of the refrigerating compartment R with the predetermined minimum temperature Trmin of the refrigerating compartment R (S5).
The predetermined minimum refrigerating compartment temperature Trmin corresponds to a temperature obtained by deducting a predetermined temperature tolerance to a desired refrigerating compartment temperature set by the user.
The control unit 46 closes the damper 24 when it determines that the temperature Tr of the refrigerating compartment R is less than the predetermined minimum temperature Trmin of the refrigerating compartment R (S6).
When the damper 24 is closed, the cold air is discharged into the refrigerating compartment R no longer. Accordingly, the interior of the refrigerating compartment R is not over-cooled.
On the other hand, if it is determined at step S1 that the temperature Tf of the freezing compartment F is less than the predetermined maximum temperature Tfmax of the freezing compartment F, the control unit 46 then compares the temperature Tf of the freezing compartment F with the predetermined minimum temperature Tfmin of the freezing compartment F (S7).
The predetermined minimum freezing compartment temperature Tfmin corresponds to a temperature obtained by deducting a predetermined temperature tolerance to a desired freezing compartment temperature set by the user.
When it is determined that the temperature Tf of the freezing compartment F is less than the predetermined maximum temperature Tfmax of the freezing compartment F, the control unit 46 turns off the compressor 41 and compressor cooling fan 42.
In the OFF state of the compressor 41, the refrigerant temperature of the evaporator 20 increases with the lapse of time. As a result, the temperature of the cold air circulating between the freezing compartment F and the evaporator 8 is increased due to a load in the freezing compartment F, so that the interior of the freezing compartment F is not over-cooled.
Thereafter, the control unit 46 again compares the temperature Tr of the refrigerating compartment R sensed by the refrigerating compartment temperature sensor 45 with the predetermined maximum temperature Trmax of the refrigerating compartment R (S9).
When it is determined that the temperature Tr of the refrigerating compartment R is equal to or more than the predetermined maximum temperature Trmax of the refrigerating compartment R, the control unit 46 again opens the damper 24, and again turns on the circulating fan (S10).
When the damper 24 is opened, and the circulating fan 10 is turned on, a part of the air cooled by the evaporator 8 is discharged into the refrigerating compartment R via the cold air discharge duct 21. The discharged cold air cools the interior of the refrigerating compartment R to a desired refrigerating temperature while being convected in the interior of the refrigerating compartment R. Subsequently, the cold air flows toward the lower portion of the refrigerating compartment R, and then returns to the evaporator 8 through the cold air return duct 22.
On the other hand, if it is determined at step S9 that the temperature Tr of the refrigerating compartment R is less than the predetermined maximum temperature Trmax of the refrigerating compartment R, the control unit 46 then again compares the temperature Tr of the refrigerating compartment R with the predetermined minimum temperature Trmin of the refrigerating compartment R (S11).
The control unit 46 again closes the damper 24 and turns off the circulating fan 10 when it determines that the temperature Tr of the refrigerating compartment R is less than the predetermined minimum temperature Trmin of the refrigerating compartment R (S12).
When the damper 24 is closed, and the circulating fan 10 is turned off, the cold air is discharged into the refrigerating compartment R no longer. Accordingly, the interior of the refrigerating compartment R is not over-cooled.
However, the above mentioned convention refrigerator temperature control method has a limitation in uniformly convecting the cold air, discharged into the refrigerating compartment R, in the interior of the refrigerating compartment R. For this reason, in the refrigerating compartment R, there may be an insufficiently cooled region where convection of the cold air is ineffectively carried out. As a result, there may be a temperature deviation in the refrigerating compartment R.
In order to eliminate such a temperature deviation in the refrigerating compartment R, a proposal for separately discharging cold air into the insufficiently cooled region has been made. In accordance with this proposal, a second cold air discharge duct is provided in the interior of the barrier 2, and a nozzle is connected to the second cold air discharge duct while being arranged such that it injects cold air into the insufficiently cooled region. In accordance with such a configuration, it is possible to more or less reduce the temperature deviation of the refrigerating compartment R caused by the non-uniform cold air convection. However, such a temperature deviation reduction is low in a state in which both the nozzle and the damper 24 are opened.